U.S. Pat. No. 4,607,197 discloses a linear and rotary electromagnetic device which is adapted as a linear and rotary stepper or stepper motor. A cylindrical movable member or armature is provided, which is mounted for both axial movement and angular movement. The armature member has teeth on its surface formed in both axial rows and circumferential alignment or rows. Stator means haying poles with windings associated with the poles is provided, the stator means having a central opening in which the movable armature member is mounted for axial and angular movement. By energizing certain angularly spaced windings, the movable armature member may be caused to rotate. By energizing axially spaced windings, the movable member of the armature can be caused to move axially. Simultaneous angular and axial movement is achieved by energizing appropriate windings.
GB 2373643 A discloses a method of manufacturing a stator for a linear-motion electrical machine. The stator comprises a plurality of stator units. Each stator unit comprise a plurality of stator poles equally angularly spaced around the circumference of the unit, and an identical number of permanent magnets which are fastened on successive stator poles and magnetized with alternating polarity. The stator units are joined axially to one another in such a way that permanent magnets of alternating polarity lie adjacent to one another on axially mutually aligned stator poles of the stator units. The stator units are prefabricated separately from one another, including the fitting and magnetization of the permanent magnets, and are then put together to form the stator.